SAT Math : SAT Mathematics

Study concepts, example questions & explanations for SAT Math

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Example Questions

Example Question #1 : Number Line

Gre12

If the tick marks are equally spaced on the number line above, what is the average (arithmetic mean) of x, y, and z?

Possible Answers:

5

8

6

4

7

Correct answer:

6

Explanation:

First, we must find out by how much they are spaced by. It cannot be 1, since 4(4) = 16, which is too great of a step in the positive direction and exceeds the equal-spacing limit. 2 works perfectly, however, as 4(2) equals 8 and fits in line with the equal spacing.

Next, we can find the values of x and y since we are given a value of 6 for the third tick mark. As such, x (6 – 4) and y (6 – 2) are 2 and 4, respectively.

Finally, z is 4 steps away from y, and since each step has a value of 2, 2(4) = 8, plus the value that y is already at, 8 + 4 = 12 (or can simply count).

Finding the average of all 3 values, we get (2 + 4 + 12)/3 = 18/3 = 6.

Example Question #2 : How To Find Value With A Number Line

How many numbers 1 to 250 inclusive are cubes of integers?

Possible Answers:

8

5

7

4

6

Correct answer:

6

Explanation:

The cubes of integers from 1 to 250 are 1, 8, 27,64,125,216.

Example Question #1 : Other Number Line

Slide1

On the number line above, the tick marks are equally spaced. Which of the following expresses  in terms of ?

Possible Answers:

Correct answer:

Explanation:

If  is between  and  on the number line, then  and .

So  must be correct because 

.

Example Question #1 : How To Find The Least Common Multiple

How many positive integers less than ten thousand are multiples of both eight and eighteen?

 

Possible Answers:

138

139

72

70

555

Correct answer:

138

Explanation:

In order to find all of the numbers that are multiples of both 8 and 18, we need to find the least common mutliple (LCM) of 8 and 18. The easiest way to do this would be to list out the multiples of 8 and 18 and determine the smallest one that is common to both. 

First, let's list the first several multiples of eight:

8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88 . . .

Next, we list the first several multiples of eighteen:

18, 36, 54, 72, 90, 108, 126, 144 . . .

By comparing the multiples of eight and eighteen, we can see that the smallest one that they share is 72. Thus, the LCM of 8 and 18 is 72.

Because the LCM is 72, this means that every multiple of 72 is also a multiple of both 8 and 18. So, in order to find all of the multiples less than ten thousand that are both multiples of 8 and 18, we simply need to find how many multiples of 72 are less than 10000, and to do this, all we have to do is to divide 10000 by 72.

When we divide 10000 by 72, we get 138 with a remainder of 64; therefore, 72 will go into ten thousand 138 times before it exceeds ten thousand. In other words, there are 138 numbers less than 10000 that are multiples of 72 and, by extension, also multiples of both 8 and 18. 

The answer is 138.

Example Question #2 : How To Find The Least Common Multiple

What is the least common multiple of ?

Possible Answers:

Correct answer:

Explanation:

 are different kind of numbers. We have a composite number and a prime number, respectively. They share a factor of . Therefore, we just multiply both numbers to get an answer of .

Example Question #1581 : Sat Mathematics

What is the least common multiple of ?

Possible Answers:

Correct answer:

Explanation:

Least common multiple is the smallest number that is divisible by two or more factors. Since  are prime numbers and can't be broken down to smaller factors, we just multiply them to get  as our answer. 

Example Question #2 : How To Find The Least Common Multiple

What is the least common multiple of ?

Possible Answers:

Correct answer:

Explanation:

We are inclined to multiply the numbers out however, if we divide both numbers by , we get  remaining. These numbers are unit and prime numbers respectively and only share a factor of . To determine the least common multiple, we multiply the factor with the numbers remaining. Our answer is just  or 

Example Question #2 : How To Find The Least Common Multiple

What is the least common multiple of ?

Possible Answers:

Correct answer:

Explanation:

Both  are even so we can divide both numbers by  to get . We have a prime number and a composite number, respectively. They share a factor of . To determine the least common multiple, we multiply the factor with the numbers remaining. Our answer is just  or 

Example Question #2 : How To Find The Least Common Multiple

What is the least common multiple of ?

Possible Answers:

Correct answer:

Explanation:

Both numbers are divisible by , so the remaining numbers are . We have a prime number and a composite number respectively. They share a factor of . To determine the least common multiple, we multiply the factor with the numbers remaining. Our answer is just  or 

Example Question #3 : How To Find The Least Common Multiple

What is the least common multiple of ?

Possible Answers:

Correct answer:

Explanation:

If we divide  for both  numbers, we get . We do it the second time and we get . Now we have a unit and a prime number. So we just multiply the factors and the remaining numbers to get  or 

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